To test carving tools for sharpness, nothing beats trying them on a piece of
wood. Across the grain you can see where more work is needed. The best way
to sharpen a knife to cut rope is on concrete. This makes a really terrible
edge (for woodworking) but leaves plenty of teeth for severing the rope
fibers.

wrote in message
oups.com...
I watched a show on the tube where they were sharpening knives and then
using the fleshy parts of their thumbs and fingers to test for
sharpness. My Dad could somehow make anything sharp enough to shave
with, and taught me to drag the end of my fingernail lightly along the
edge, a slight resistance meaning scary sharp.